With years of development of light-emitting diode (LED), the III-V group compound is the mainstream semiconductor material for fabricating a light-emitting diode, in particular, the GaN-based and AlGaInP-based materials. Conventional P-type III-V group semiconductor material has poor current spreading performance. To enable uniform injection of current into the light-emitting layer, a current spreading layer is added over the P-type material layer. Among materials of the current spreading layer (TCL), the indium tin oxide (ITO), cadmium tin oxide (CTO), indium oxide (InO) and zinc oxide (ZnO) can improve the current spreading effect. Among them, ITO is most widely applied, which is a semiconductor functional material with excellent photoelectric property featuring high visible light transmittance (>80%), low resistivity (10−3-10−4 Ω·cm), large band gap (3.6-3.9 eV) and high refractive index (1.8-2.0).